Most traditional residential construction is still carried out utilizing conventional methods and materials such as wood or metal frame structural components, masonry block, precast concrete panels, and cast-in-place concrete forms. These types of construction are universally recognized, but they require a high degree of sophistication and training in order for them to be useful. Most of these traditional construction methods are both costly and time-consuming.
Large numbers of “prefab” or “modular” building systems have been brought to the market in recent years. These systems require a central manufacturing facility, and experience high acquisition and transportation costs for all the necessary materials. These modular construction methods also sacrifice the ultimate durability and longevity of the resulting structure, where too much emphasis has been placed on cost-reduction in order to meet limited construction budgets.
There has been some utilization of pressurized concrete or “shotcrete” for wall construction over the past few years. Shotcrete has unique qualities such as high strength, crack resistance, prolonged durability, and low permeability, making it much more water resistant and more resistant to seismic activity than other forms of concrete. There have been several wall systems over the years that use shotcrete or pressurized concrete, none of which has been highly successful.
The two most common types of shotcrete wall systems use either a Styrofoam core to which shotcrete is applied, or a steel panel of some description to which shotcrete is applied. Both of these methods generally require shotcrete to be applied to both sides of the wall. The Styrofoam panel system is inherently weaker, and therefore, makes it less durable and less suitable where high wind or seismic conditions exist. The systems that use various types of steel mesh to which the shotcrete is applied are much stronger, and as a result, they are more durable. The problem with these systems is that it is more difficult to apply the shotcrete to the walls because there is no rigid panel or diaphragm on which to place the shotcrete during the application process. The more the panels or diaphragms move during application, the more difficult it is to get the shotcrete to adhere to the panel surface, where the flexing of the panels increases the rebound effect of the shotcrete, resulting in unacceptable amounts of wasted concrete.
There is still much room for improvement when utilizing shotcrete to form the primary walls in any type of structure. The construction market needs a concrete and steel mesh building system that is strong, fast, and economical. The necessary building system and process to achieve these goals cannot require excessive amounts of costly skilled labor and cannot create excessive amounts of wasted materials.